Coatings for hard and soft surfaces are important for the protection of the surface and can add to the aesthetic appeal to natural surfaces, such as wood. Concerns about emissions of volatile organic compounds (VOCs) along with stricter legislation on VOCs have led to an increased focus on the use of water based systems for coating applications. Water based systems offer the additional advantages as they are easier to use than solvent based coatings.
Polyurethane dispersions (PUDs) may be used for a wide range of commercial applications, such as coatings for textile fabrics, plastics, wood, glass fibers and metals. The production of polyurethane-urea dispersions is known, as exemplified in U.S. Pat. Nos. 4,237,264; 4,408,008; 5,569,706; U.S. Patent Publications 2004204559; 2005004367; GB Patent Publication 2386898 and WO Publication 2005023947.
Regardless of the property levels of coatings prepared from commercial PUDs, there continues to be a need to improve the coating properties of PUDs used in hard coatings for surfaces, such as wood. It as an object of the present invention to provide aqueous PUDs for hard surface coating which are capable of forming a film at ambient temperature without the need for a coalescing solvent. In addition, the aqueous PUDs give a hard, solvent resistant coating.